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This is the blog maintained by staff at Microsoft to provide general information, announcements and provide answers to Frequently Asked Questions (FAQs) related to daylight saving time (DST) and time zone (TZ) changes around the world.
* Important Notice

Microsoft is preparing update to address recent time zone data changes in Chile and Mexico. Details are as below:
Chile will remain in DST from this year on, thus its UTC offset will be updated to UTC-3:00, display name of time zone "Pacific SA...

The December 2014 DST Cumulative Update for Windows Operating Systems is now available. It contains the following changes:
Russia time zones Russia has changed its existing time zones on October 26, 2014. This change included seven updated time...

Fiji government announced on Oct. 20th, 2014 that Fiji will enter DST on November 2nd, 2014 till Jan 18th, 2015 ( link ). While Microsoft is preparing a Hotfix to address this change, below are temporary solutions that users who are impacted by this change...

According to a recent law [ link ] passed by the government of Russia, Russia will change its existing time zones on October 26, 2014.
Microsoft is planning to release an update for Windows on September 23, 2014 to address this change, with details...

The August 2014 DST Cumulative Update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes:
Jordan Standard Time: For 2014 and onward, Jordan has changed its DST Start time from the last...

The government of Egypt has decided to pause DST during the holy month of Ramadan in 2014, from Friday, June 27 at 00:00 to Friday, August 1 at 00:00.
Fix it solutions for Windows have been released to address this change, and you can find the details...

The government of Morocco has decided to pause DST during the holy month of Ramadan in 2014, from Saturday, June 28 at 3AM to Saturday, August 2 at 2AM.
Fix it solutions for Windows have been released to address this change, and you can find the details...

This time zone update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes:
Chile
Chile has changed its DST start date to September 7 at 00:00:00 and DST end date to April 27...

This time zone update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes:
Jordan: Jordan announced last year that, on December 20, 2013, it would no longer use the daylight saving...

The December 2013 DST Cumulative Update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes:
Mid-Atlantic Time: The Mid-Atlantic time zone is deprecated in this update.
Morocco...

The August 2013 DST Cumulative Update for Windows Operating Systems has been published on Microsoft Download Center. It contains the following changes:
Libya Standard Time:
New DST starts on the last Friday of March at 2:00 A.M., and ends...

The government of Paraguay has Shortened Daylight Saving Time for 2012-13 [ Official Decree ]. DST for Paraguay now ends on March 23, 2013.
A hotfix for Windows has been released to address this change. You can find details of the hotfix and download...

The government of Chile has extended Daylight Saving Time for 2013 [ Official Decree ]. DST for mainland Chile now ends on April 27, 2013 and starts on September 7, 2013.
A hotfix for Windows has been released to address this change. You can find details...

This hotfix contains three new changes in Windows Daylight Saving Time support:
The government of Israel extended Daylight Saving Time to a period of 193 days.
Starting 2013, DST in Israel will now begin on the Friday before the last Sunday...

The December 2012 DST Cumulative update for Windows operating systems has been published on Microsoft Download Center. It contains the following changes:
Bahia Standard Time: Starting in 2012, Bahia Standard Time will no longer have DST.
...

The October 2012 DST Cumulative update for Windows operating systems has been published on Microsoft Download Center. This year’s October Update replaces the normal August Cumulative Update. It contains the following changes:
E. Europe Standard...

As stated in the previous blog post , Microsoft has issued updates for Morocco introducing Daylight Saving Time in 2012 [ KB2698707 ].
Daylight time will be paused during the holy month of Ramadan. Due to the yearly fluctuation of the start and...

According to a recent law [ link ] passed by the government of Morocco, Morocco will follow DST each year from 2012.
Microsoft is releasing a series of updates for Windows to address this change. You can find details of the updates, including order...

Disclaimer : The information in this document is written in response to an announcement by the government of Armenia about changes in the daylight saving time in Armenia for the year of 2012.
The steps provided in this bulletin were created to mitigate...

The government of Chile has extended Daylight Saving Time for 2012 [ Official Decree ]. DST for mainland Chile now ends on April 28, 2012 and starts on September 1, 2012.
A hotfix for Windows has been released to address this change. You can find...

The December 2011 DST Cumulative update for Windows operating systems has been published on Microsoft Download Center. It contains the following changes:
Kaliningrad Standard Time: As previously announced in KB2625508 , Belarus has decided to discontinue...

The previous post calls out planned 2011 DST cancellations for Belarus, Ukraine and Armenia [ link ].
We have received reports that Armenia and Ukraine have canceled their proposed changes. According to reports in Rada and Kyivpost , Ukraine will not...

Ukraine , Belarus , and Armenia have decided to discontinue daylight saving time starting from 2011. These countries are mirroring Russia's changes by staying on "summer time" indefinitely and not falling back to "winter time" on October 30th 2011. Microsoft’s...